The Real Story Behind the Iconic 'Friday the 13th' Whisper Sound Effect

Spooky season is here, and Camp Crystal Lake is open for business again. With the brand-new prequel series Crystal Lake out now and Halloween right around the corner, It's fitting timing to dive into the story behind the iconic Jason sound effect.

Two syllables. Whispered, echoed, and repeated until the woods around Crystal Lake start closing in. Ask a horror fan to do the Friday the 13th sound, and you'll almost always hear the same thing: ch-ch-ch, ah-ah-ah .

Close, but no machete. The real words hiding in that whisper are far creepier, and the man who made it says they came straight from the killer's own mouth.

It's Not "Ch-Ch-Ch, Ah-Ah-Ah"

According to composer Harry Manfredini, the whisper is actually ki-ki-ki, ma-ma-ma .

Spoiler alert for a 46-year-old movie: those syllables come from one line near the end of the original 1980 Friday the 13th . Pamela Voorhees (Betsy Palmer), slips into the childlike voice of her drowned son, Jason, and urges herself on: "Kill her, Mommy!"

Manfredini clipped "kill" down to ki and "mommy" down to ma . The result is meant to be the voice in Pamela's head, a son egging his mother on from beyond the grave.

A Whisper and an Echo Box

There was no elaborate studio trickery. Manfredini whispered the syllables into a microphone, then ran them through an Echoplex, a tape-delay unit that was cutting-edge gear at the time. The echo smeared and repeated each sound, which is a big reason ears hear ch and ah instead.

The idea started when director Sean S. Cunningham asked for some kind of choir. Manfredini thought instead of Polish composer Krzysztof Penderecki, whose avant-garde music uses sharp, jarring vocal sounds. Two whispered syllables became the film's entire choir.

The Sound of Being Watched

Friday the 13th had a problem: audiences don't see the killer until the final act. Much of the stalking plays out through the killer's point of view, and a shaky camera alone isn't scary.

In a 2020 interview, he recalled suggesting that music play only when the camera shows the killer's viewpoint. Like the two-note shark theme in Jaws , the whisper became an alarm: hear it, and someone is watching.

He pulled it off on a shoestring, too. The budget covered just a handful of musicians, so layering did the heavy lifting.

Settling the Spelling

Fans still argue about it, and there's no official way to spell a sound effect. But Manfredini has been consistent. He laid out ki and ma in a 2015 interview with Gun Media, and 2017's Friday the 13th: The Game printed it right on a loading screen.

So the next time you hear those whispers, remember: that's not Jason talking. It's his mother, talking to herself.

Looking For More Frights?

This October, Ripley’s in Grand Prairie stops being an Attraction and starts being a problem.

Walk into Ripley’s Mirror Maze with no obvious way out. Pass through the Wax Museum of Fear, where the figures are a little too still, a little too close, and not all of them are wax. Then test your courage on the 7D Werewolf Ride.

One ticket gets you all three, and live scare actors are back to make sure you second-guess every corner.

Event Details

Dates: October 24

Time: 7–11 p.m.

Price: $29.99 +tax

Includes: Ripley’s Mirror Maze, Wax Museum of Fear, and 7D Werewolf Ride

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